The human eye is sensitive light over a very wide range of intensities. Images must have high dynamic ranges to accurately reproduce real scenes. High-performance image sensors, such as high-performance CCD arrays are capable of acquiring images having high dynamic ranges. There are displays, such as the displays available from Dolby Canada Corporation are capable of displaying high dynamic range images. However, many computer displays, televisions and the like have limited dynamic ranges and are incapable of displaying such high dynamic range images.
Some image data has low dynamic range because of the way that the image data is acquired or generated. In other cases, the dynamic range of image data may be reduced to match the characteristics of displays on which image of the image data will be reproduced. A tone mapping operator can be applied to higher dynamic range image data to reduce the dynamic range of the image data. This may be done, for example, to provide image data that matches the dynamic range of a type of display or a particular image data format.
There is a vast amount of existing image data that has a dynamic range that is lower than the dynamic range that can be displayed by available high dynamic range displays and/or appreciated by the human eye.
There is a need for methods and apparatus that can boost the dynamic range of lower dynamic range image data.